The present invention relates to a radio paging system, and more particularly to a radio paging system enabling a battery saving function at each of its battery-powered receivers.
Battery saving systems of this kind include the "Digital Radio Paging Communication System" of Masaki et al., disclosed in on U.S. Pat. No. 4,194,153, issued on Mar. 18, 1980 and assigned to the present applicant (now known as NEC Corporation). In the battery saving system proposed by Masaki, a paging receiver intermittently operates at a predetermined first repetition period. When a base station transmits a battery saving release signal lasting longer than the first repetition period, the receiver continuously operates for a duration (longer than the total duration of the battery release signal and the base station's transmitted paging signal) to receive a paging signal. When this time has elapsed, the paging receiver again returns to its original intermittent operation.
In this prior art system, the first repetition period of each paging receiver is usually set so as to process calls adequately when system traffic is at its peak. Even when the base station transmits paging signals much less frequently, as, for example at night, each paging receiver still regularly repeats its intermittent operation, resulting in a waste of receiver battery power. This disadvantage has been handled by turning off the receiver's power supply at night. However, the paging receiver then misses paging signals.